Prepare the egg and cheese mixture: In a medium bowl, whisk together the 2 whole eggs and 2 egg yolks. Add the finely grated Pecorino Romano cheese and about half of the freshly ground black pepper. Mix thoroughly with a fork or whisk until a thick, cohesive paste forms. Set aside.

Cook the pancetta: Place the cubed or diced pancetta in a large, cold skillet or frying pan. Turn the heat to medium-low. Cook slowly, stirring occasionally, allowing the fat to render out and the pancetta to become golden brown and crispy. This process should take about 10-15 minutes. Do not rush this step, as slow rendering is key to crispy pancetta and flavorful fat.

Remove pancetta and reserve fat: Once the pancetta is crispy, use a slotted spoon to remove it from the skillet and set it aside on a plate lined with paper towels. Leave the rendered fat in the skillet. If there's an excessive amount of fat (more than 3-4 tablespoons, or 45-60ml), you can carefully pour off the excess, leaving about 2-3 tablespoons (30-45ml) in the pan.

Boil the pasta: While the pancetta is cooking, bring a large pot of water to a rolling boil over high heat. Add a generous amount of salt to the water (about 1-2 tablespoons, or 15-30g). Add the spaghetti and cook according to package directions until al dente, typically 8-10 minutes. Ensure the pasta is cooked through but still has a slight bite.

Reserve pasta water: Just before draining the pasta, scoop out about 1 cup (240ml) of the starchy pasta water. This water is crucial for creating the creamy sauce and emulsifying the ingredients.

Combine pasta and fat: Drain the spaghetti thoroughly and immediately add it to the skillet with the reserved pancetta fat. Toss the spaghetti in the fat over medium heat for about 1 minute to coat the strands and absorb some flavor. Remove the skillet from the heat. This step is critical to prevent the eggs from scrambling.

Temper the egg mixture: Add about 1/4 cup (60ml) of the hot reserved pasta water to the egg and cheese mixture, whisking vigorously. This tempering process gently heats the eggs, making them less likely to scramble when added to the hot pasta.

Create the sauce: Pour the tempered egg and cheese mixture over the hot spaghetti in the skillet (which is off the heat). Immediately begin tossing the pasta vigorously with tongs. The residual heat from the pasta and the pan will cook the eggs and melt the cheese, creating a creamy sauce. Keep tossing continuously.

Emulsify and adjust consistency: Add the crispy pancetta back into the skillet. Continue tossing and stirring. If the sauce seems too thick or dry, gradually add more of the reserved pasta water, a tablespoon (15ml) at a time, tossing continuously until you achieve a smooth, glossy, and creamy consistency that coats the spaghetti beautifully. Do not add too much water at once.

Season and serve: Add the remaining freshly ground black pepper and toss again. Taste and adjust seasoning if necessary, though the pancetta and Pecorino Romano are usually salty enough. Serve immediately in warm bowls. Garnish with extra grated Pecorino Romano cheese and a final grind of black pepper.